The first Nancy Drew book, 1930's The Secret of the Old Clock, was ghostwritten by Mildred Wirt, who penned 23 Nancy Drew titles as Carolyn Keene—the same pseudonym used today. An original edition can bring $5,000 in mint condition; Wirt's autograph doubles this copy's value to $10,000. Eight years after the novel's debut, the series spawned a movie, Nancy Drew: Detective. A lobby card from that film now sells for up to $800.

1940s

1940s

In the 1940s, Nancy's new hairdo, an au courant Lauren Bacall style, came courtesy of illustrator Russell Tandy, who drew all but one of the series' covers between 1930 and 1949. The heroine's gutsy demeanor remained much the same during this decade, as did plotlines--often about heists or missing heirs. Both themes appear in 1943's The Clue in the Jewel Box, which earns an appraisal of $200.